Manufacture of diamino-diaryl-urea



Patented Feb. 15, 1927.

FRITZ HEINZE, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSIGNOR TO I. G.

FABBENINDUSTRIE .AKTIENGESELLSCHAFT, OF FRANKFORT-ON-THE-MAIN, GER- MANY, A CORPORATION OF GERMANY.

MANUFACTURE OF DIAMINO-DIARYL-UREA.

1V0 Drawing. Application filed May 27, 1926, Serial No. 112,126, and in Germany June 10, 1925.

It is known to prepare p.p-diamino-dihenyl-urea by reducing p.p'-dinitro-caranilide by means of tin and hydrochloric acid or by melting urea with mono-acetyl-pphenylene-diamine and saponifying the resulting di-acetyl 00m und.

Ihave now foun that urea reacts also with, non acetylated p-phenylene-diamine with the. formation of p.p-d1amino-diphenyl-urea. Preferably the reaction is carried out at an elevated tem erature and in the presence of an inert iluent. Instead of p-phenylene-diamine its derivatives substituted in the nucleus may also be employed.

The following examples will further illustrate how my present invention may be carried out in ractice, but the invention is not limited to 1; ese examples. The parts are by weight.

- Example 1.

A mixture of parts of urea, 216 parts of pphenylene-diamine and 600 arts of o-dich or-benzene is slowly heate to 130 C. When the evolution of ammonia is finished, the o-dichlor-benzene is distilled off by means of steam; the residue is dissolved in dilute hydrochloric acid and the solution is filtered. p.p' diamino diphenyl urea is obtained therefrom with a good yield by precipitation by means of sodium carbonate.

Example 2. A of 60 parts of urea, 262 parts of 2.5-toluylene-diamine and 600 parts of trichlor-benzene is heated to to until the evolution of ammonia is-finished. The trichlor-benzene is distilled 01f by means of steam and the residue is worked up in the manner described in Exam le 1.- 4.4'-diamino-3.3-dimethy1-dipheny -urea is obtained with a good yield.

Emample 3.

576 parts of p-phenylene-diamine are intimately mixed with parts of urea and heated to 110. to 120 C. in a vessel standing in a hot air bath. After the evolution of.

ammonia is finished the product is dissolved in dilute hydrochioric' acid and filtered. From the filtrate p.p'-diamino-diphen l-urea 1s precipltated by means of sodium car clalm: 1. The process of preparing diamino-diphenyl-ureas which consists in acting on a p-phenylene-diamine with urea.

onate.

2. The process of preparing diamino-di- FRITZ HEINZE. 

